PiT: a new allele in the alpha 1-antitrypsin system.

In a genetic investigation of the population in Hessen, Germany, we found a family with a new, rare allele in the Pi system (alpha 1-antitrypsin). According to electrophoretic analysis and isoelectric focusing patterns, it is designated PiT. A pedigree study suggests autosomal codominant inheritance. The serum concentration of six heterozygous carriers of this allele (phenotype M1T or M2T) revealed normal alpha 1-antitrypsin levels.